The main characteristic of FroBot is the dual-swing-legs propulsion mechanism, and it is necessary for us to conduct a series of experiments to study its propulsion model, both on land and underwater. As the propulsio...
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This paper provides a complete solution for landing a quadrotor Unmanned Aerial Vehicle (UAV) on an Unmanned Ground Vehicle (UGV) in the outdoor environment. An image-based visual servo control law and a GPS-based nav...
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ISBN:
(纸本)9781509023974
This paper provides a complete solution for landing a quadrotor Unmanned Aerial Vehicle (UAV) on an Unmanned Ground Vehicle (UGV) in the outdoor environment. An image-based visual servo control law and a GPS-based navigation method are proposed, and the former method acquires the visual feedback from the camera attached to the quadrotor, while the latter strategy is used when the visual feedback is absent. For achieving more precise and stable performance in visually guided landing process, we design a specific landing marker that can provide different features as the distance between the quadrotor and landing target changes. Meanwhile, the corresponding detection and recognition algorithms are raised. Finally, a simulation experiment is carried out to validate the proposed vision algorithms and control strategies.
We investigate the basin of attraction properties and its boundaries for chimera states in a circulant network of Hénon maps. It is known that coexisting basins of attraction lead to a hysteretic behaviour in the...
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We investigate the basin of attraction properties and its boundaries for chimera states in a circulant network of Hénon maps. It is known that coexisting basins of attraction lead to a hysteretic behaviour in the diagrams of the density of states as a function of a varying parameter. Chimera states, for which coherent and incoherent domains occur simultaneously, emerge as a consequence of the coexistence of basin of attractions for each state. Consequently, the distribution of chimera states can remain invariant by a parameter change, as well as it can suffer subtle changes when one of the basins ceases to exist. A similar phenomenon is observed when perturbations are applied in the initial conditions. By means of the uncertainty exponent, we characterise the basin boundaries between the coherent and chimera states, and between the incoherent and chimera states, respectively. This way, we show that the density of chimera states can be not only moderately sensitive but also highly sensitive to initial conditions. This chimera's dilemma is a consequence of the fractal and riddled nature of the basins boundaries. Coupled dynamical systems have been used to describe the behaviour of real complexsystems, such as power grids, neuronal networks, economics, and chemical reactions. Furthermore, these systems can exhibit various kinds of interesting nonlinear dynamics, e.g. synchronisation, chaotic oscillations, and chimera states. The chimera state is a spatio-temporal pattern characterised by the coexistence of coherent and incoherent dynamics. It has been observed in a great variety of systems, ranging from theoretical and experimental arrays of oscillators, to in phenomena such as the unihemispheric sleep of cetaceans. We study the chimera state in a circulant network of Hénon maps, seeking to determine how the density of states in the network depends on the system parameters and the initial conditions. We have found that, as expected, the density of states might be inva
In this paper, a new kind of liquid-circular angular accelerometer is studied. Based on electrokinetic phenomenon, this angular accelerometer is designed with a porous transducer and fluid mass. Due to the existence o...
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ISBN:
(纸本)9781467392211
In this paper, a new kind of liquid-circular angular accelerometer is studied. Based on electrokinetic phenomenon, this angular accelerometer is designed with a porous transducer and fluid mass. Due to the existence of electrical double layer between transducer and fluid mass, this angular accelerometer is able to convert angular acceleration input to electrical signal. The whole system is composed of fluidic system and molecular electronic system. Theoretical analysis and several experiments are implemented to obtain transfer function model of fluidic system. The flow in transducer satisfies the Darcy Law in the experiment and angular velocity input is proved to have no effect on the output. A prototype is designed to compare the output of theoretical model and experiments. All of the experiments prove that the fluidic system of this liquid-circular angular accelerometer can be seen as a first-order system, especially when the frequency of input is less than 30Hz and its transfer function is derived.
Accurate terrain estimation is essential for unmanned ground vehicle (UGV) to achieve autonomous navigation. However, some existing approaches are difficult to reconstruct the 3D surface in real-time because of seriou...
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ISBN:
(纸本)9781509041039
Accurate terrain estimation is essential for unmanned ground vehicle (UGV) to achieve autonomous navigation. However, some existing approaches are difficult to reconstruct the 3D surface in real-time because of serious amount of computation. A method of environmental terrain estimation based on multi-scale radial basis function with a 3D lidar mounted on a moving vehicle was proposed in this paper. By combining kernel template with terrain grid map, the approach is applicable to the non-uniform density distribution of laser point cloud with the increasing detection range and improves the efficiency of calculation. What's more, the estimation of culverts and trees will be more accurate if treat the point cloud in separate layers for suspended obstacles problem. All terrain estimation approaches were verified with good performance in an interactive system, which is set up with Virtual Robot Experimentation Platform (VREP) and actual vehicle.
In this paper, we first propose a self-tuning adaptive distributed observer for a multi-agentsystem, which is capable of providing the estimation of the leader's signal to various followers without assuming all t...
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ISBN:
(纸本)9781467386838
In this paper, we first propose a self-tuning adaptive distributed observer for a multi-agentsystem, which is capable of providing the estimation of the leader's signal to various followers without assuming all the followers know the system matrix of the leader and which avoids calculating the observer gain off-line. We then further develop an adaptive distributed control law to solve the cooperative output regulation problem for linear heterogeneous multi-agentsystems. This control law offers two advantages in that it makes the least use of the information of the network and the information of the leader system, and it avoids calculating the observer gain.
In this work, we report the set-up and results of the Liver Tumor Segmentation Benchmark (LiTS), which was organized in conjunction with the IEEE International Symposium on Biomedical Imaging (ISBI) 2017 and the Inter...
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Recently, the UGV (Unmanned Ground Vehicle) receives more and more attention from the public with the application in deep space exploration, national defense, and riot relief. Moreover, how to describe the driving env...
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ISBN:
(纸本)9781467376648
Recently, the UGV (Unmanned Ground Vehicle) receives more and more attention from the public with the application in deep space exploration, national defense, and riot relief. Moreover, how to describe the driving environment of UGV with the sensor data objectively and share these data with other UGV efficiently becomes the focus of the research of the UGV. To solve the above problems, a novel GIS platform for UGV application in the unknown environment is proposed in this paper based on the features of UGV. First, the GIS database is redesigned and the properties such as road width, lane number, lane info, and if_traffic are proposed. The data structure of the database is redesigned to fit the need of UGV to describe the environment simply and explicitly. Then a two-line road model is proposed to model the feature of the road network clearly. This model can meet the driving need of UGV and represent the traffic rules of the urban environment. Moreover, the turning path in the intersection is designed to be an arc instead of a right angle path considering the dynamic features of UGV. Finally a cost map for navigating the UGV locally is generated with the road model and the environment information from the sensors. The GIS platform designed in this paper proves to be able to offer guidance and help to UGV for driving through the unknown environment wisely and quickly without human intervention. And it shows promising application of sharing data with other UGV efficiently by using cost map instead of the original sensor data.
An adaptive distributed differential evolution algorithm is proposed based on the change of the individual's fitness value. Firstly, the initial population is divided into several subpopulations. When the migratio...
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An adaptive distributed differential evolution algorithm is proposed based on the change of the individual's fitness value. Firstly, the initial population is divided into several subpopulations. When the migration condition is satisfied, the best individual in each subpopulation will replace the worst individual of its neighbor subpopulations according to the Von Neumann topology. The migration mechanism among subpopulations enables the information to be communicated in the whole population. Meanwhile, the adaptive mechanism of F and CR is presented for assigning different F and CR to each individual according to the individual's fitness. Numerical results show that, the proposed algorithm is beneficial to explore the solution space, which can avoid the premature convergence and search the excellent solutions.
To resemble the appearance of human beings, humanoid robots should be designed with many DOFs, however, it increases the complexity of the mechanical design and the real-time control, which will make a high cost and h...
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ISBN:
(纸本)9781479973989
To resemble the appearance of human beings, humanoid robots should be designed with many DOFs, however, it increases the complexity of the mechanical design and the real-time control, which will make a high cost and have a poor reliability and will not fit for the application in museums or human's daily lives. In this paper, to enable the low cost and high reliability robot to interact with humans naturally and sever humans more friendly, we imported advanced technology of the Waseda's flute robot and retained the most important mechanical parts, such as the lip, lungs and the fingers for the flute playing, on this basis, some other mechanical structures were redesigned; particularly, the robot's appearance was carefully designed; in addition, we also redesigned the hardware structure using our own joint controllers and software system based on CAN bus communication for the cost saving and high reliability. The redesigned robot had just 16 DOFs. Preliminary performance test results showed that this new redesigned robot achieved in producing high quality of flute sound and high sound conversion efficiency, and the period of communication was about 4ms.
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